The present invention relates to internal combustion engines in general, and more particularly to improvements in internal combustion engines of the type wherein discrete crankshafts can be rotated by discrete groups of cylinders. This results in considerable savings in fuel and reduces the percentage of deleterious combustion products which are discharged into the atmosphere. As a rule, a single group of cylinders will be used when the engine is operated at partial load, and one or more additional groups of cylinders are used when the engine is to operate at a higher or at a maximum load. Such engines must be equipped with means for connecting the crankshaft of a second section or unit in the engine to the crankshaft of a first section or unit before the cylinders of the second group are started. Connection of the two crankshafts to each other must be preceded by acceleration of the crankshaft in the second section to the speed of the crankshaft in the first section.
An internal combustion engine with several sections or units each of which embodies a discrete crankshaft is disclosed in German Offenlegungsschrift No. 28 28 298. The cylinders are are installed in a common block and a first group of such cylinders is in use when the engine is started and also whenever the engine operates at partial load. One or more additional groups of cylinders are set in operation if the engine is to furnish more power, and this entails a requisite acceleration of corresponding crankshaft or crankshafts for the cylinders in the additional group or groups. It is necessary to accelerate a previously idle crankshaft to the speed of the rotating crankshaft or crankshafts as well as to ensure that the accelerated crankshaft will be coupled to the running crankshaft or crankshafts in a predetermined angular position so as to guarantee the firing of cylinders in a desired sequence.